_________ is used for making photographic films.

Options

A. `AgNO_(3)`
B. `KNO_(2)`
C. AgO
D. AgCl

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the substance used in making photographic films.

2. **Identifying the Options**: The options given are AgNO3 (Silver Nitrate), KNO2 (Potassium Nitrite), AgO (Silver Oxide), and AgCl (Silver Chloride).

3. **Analyzing Silver Nitrate (AgNO3)**: Silver Nitrate is produced by dissolving pure silver in nitric acid. It is a precursor for other silver compounds.

4. **Formation of Silver Halides**: When Silver Nitrate (AgNO3) reacts with halides (like chlorine, bromine, or iodine), it forms silver halides (AgX). The general reaction can be represented as:
\[ \text{AgNO}_3 + \text{Halide} \rightarrow \text{AgX} + \text{NO}_3^- \]

5. **Identifying Suitable Halides**: Among the halides, chlorine (Cl), bromine (Br), and iodine (I) can be used. However, chlorine is very reactive and not suitable for photographic films.

6. **Final Product**: The silver halides formed (AgCl, AgBr, or AgI) are used in photographic films. Among these, AgCl (Silver Chloride) is commonly used.

7. **Choosing the Correct Option**: Since the question asks specifically for the substance used in making photographic films, and AgCl is one of the silver halides formed from AgNO3, the correct answer is AgCl.

8. **Conclusion**: Therefore, the answer to the question is AgCl.

**Final Answer**: AgCl is used for making photographic films.

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